Grinding-machine.



F. E. BRIGHT.

GRINDING MACHINE.

APPucATloN FILED Ffa. 2. 1915. v

Patentedept. 19, 191

{SHEETS-SHEET l.

.n nu t m AttyS;

STWKMM F.E.BmGHT.

l GRINDING MACHINE.

APPLICATION FILED FEB.2. 1915 `Patented sept. 19, 19116.v

4 SHEETS-SHEET 2.

est:

Inventor:

- tt-yS F. E. BRIGHT.

GRINDING MACHINE.

APPLICATION FILED FEB. 2. 1915.

, 1 1 98,6 1 2 Patentedvept. 19,1916.

V 4 SHEETS- SHEET 3. E9-4 .u i 11i Ventor:

F. El BRIGHT.

GRINDING MACHINE. APPLICATION FILD EEB. 2, 1915.'

4- SHEETS-SHEET 4.

.l 1 1 98,6 1 2 Pateted Sept. 19, 1916. l

0N LINE D ranged relatively FRED E. BEGHT, HLAIGELPHI, BEENSYLVNI.

known that l Fei-'is Bere-Hr, citi- Zen oI the Uriiteel States, resicli Philofilelphia, in the county of Phila phia ariel State of Pennsylvariia, have inve seri cer tain new and useful l iii Grindmprovemeras ing-Machines, of which the lou specification, reerence being'lia the 'accompanying This inventioil reletes'to grin@ i5' ishing macliiries, sind particularly to that type siacliioe irl which the work is rotatefl wiiileibeiog sillijecteil to the aotioii of an operatiefY tool.

The invention is designecl Witx'i special reference to the handling of annular :forms or shapes, such for inst-ence as casing members or bearing; rings of aritiiricticn bearings, the particular form or" meelienism here shown as embodying; my im'erriziori7 loeing adaptable :for operating ori the bores the inner easing members or' aiitifriction bearings in order to give the bore its proper and accurate iiiisiied coiidition-l l in itsgeiieral organization, the mechanism embodying my invention comprises a holder for the work, in this iisterice the inner casing member of enantirrictioii bearing7 which holder is adapted to be rotated so as to correspi'mdingly rotate the Work about its central longitudinal axis' mal expose tlie bore of the same; a rotary tool arto the Work lioltler to er? able the tool to operate or. the inte ier of the bore;- n

i. means for moving the Atool axially of the work that it will traverse the bore lengthwise; emlmeaiis imparting a feeding movement to the tool in a radial direction to cause it to enter more deeply into the material of the Work.

ln the more speciiic embodiment of' the in ventiong the Work holding' clevice is in the form oifa cliuclr carrieci on tlieeocl o a rotatable sleeveI and the operating tool is in tlie form of a grinding Wlieel corrieri iiy e spindle extending longitudinally within the rotary sleeve and mountecifor Entrically Within a surrouutlin adjusting sleeve,. ef

for rotary oscillation in a supporti which latter is mountedv for re on within the said rotary chucki me sleeve, the reciprocating movement of the supportizigsleeve imp rtirig e trai# elsing movementto l-1e griziflmg Wheellorin gitudinal'ly or the bore of the work,

'thereof may such limitations rotation ecn liich adjusting sleeve is in turni- 'View el Sept. Mil, 1916.

oscillating movement ofthe ajusting sleeve imparting e radial feeding movement to -Athe grinding ensei aloe to the eccentric mounting of the Wheelcerrying spindle within the adjusting sleeve. The rotary chuck-carrying sleeve, simil the Wheel-carrying spindle are respectively provided with driving pulieys oy mee of which a rotary motion is ie'iparted. to sai@ devices from a suitable source of power, the reciprocating loveme'ut of the supporting sleeve being impart? eti. to the autoiilatieally by' the rotation or the cimeli-carrying sleeve, while the oscillating' movement ot the adjusting sleeve is 73 imparted thereto by hand, through -the merli" m of iieeoanism which will enable fie grinding wheel to be fed radially to the Work to predetermined and definite extents. The n'ieclianism shown in the accompanying drziwings is one form of embodiment of my invention, which is illustrated by Way of f example, and which in practice has been :toondto answer toa satisfactory degree. the objects to .be attained;` It will be'menfest, however, that the constructofnel details be variously modified and changed by the skilled mechanic Without de- Qarting from the spiritl of my invention; and it will be understood that theirvention is not limitecl to ,any particular form or construction the parts except in so far as are sp'eciiefl in the claims. ln this connection however, I believe myselz to be the irst to arrange a tool-carrying spinle within aser-rounding rotary worlecarrying sleeve or member, and to combine" therewith7 means for effecting a feeding' movement of the operating tool transverselylAk or radially with respect to the. axis of rota 95 'tion or" the Werl@v Also l" believe myself to "be the first to arrange a tool-carrying spinelle within e suiiounding rotary work carryimg-sleeve7 in combination with means t impart to the tool carryingspindle a longi?l tudinalmotion to cause the tool to traverse the Work in like direction. .v

In the 'accompanying drawings: Figure l, i is a longitudinal' section through my improveol machine with parts in elevation. rig. 2 the same. Fig. 3

1 06 is a rear elevation of is a transverse sectional elevation on the iine a-ci of Fie'. Fig; e is a similar View on the line LM?) oit Fig. l. 5 is e similiar on the line c-c oi Figli. Fig.` iis-e. herieiootal sectional plan viele' a-zi of Fig.l i. Fig. l is a sectionelview irreA on the line r which extend und are supported, hc ro ,by means uff a i 1 a, TW

of Fig. Q. Fig. S u rami Secimuxi eiemtiwn of the fume :uni cizitcii parts iiu'uugh which the tuoi spiluih; is reciprocaied.

Referring u the i1:\.\\'ing,t The upcruiin parts of he mufshixunu mountfeii in vsxi Sustained by i suituhh. :une i, vmivluisiugz n base 01 bed pini@ rom which eriiemis upwariiiy; :i from standard und :i man' standuid -LL These standards uw pi'uvided with aiineii hC/rizuutxi openings, wihiu chuck-carrying sieeve the supp sie (3, the usciiiziing mijusingr siefeve '7, and the Wheei-L'ariying spimiio S. said parte; Wihiu ih@ other in h@ reintions' above meuioneii i ijv il being fixed.

imm u power. The sive@ expueis :xi 9nd heyonfi the standard, ai which paint ii: 'w' vhui'i 1:23 Qi' 1, 'i'mni uppmt tu ihn .vm'i: zohc'upefvwted om in thel 'prfasiruiv imi-(uwe the ug; member imi-SPGM. Y iii mi nu :uifi'iclon baiting. whiuh uimuhei' is hifhi hy the chuck in Such nummer thai it 'vfiii im ioumi with the Sievv 1ofiih {hi} hunl ui thc qua Y mumiier expusizii in the uciimi oi' the giri uiiug uheei 14 mi ih@ fmuuiii @mi uf the spin- (iie The supporting i3 axiuiiy within the Sicura iii-iat ii muy im IQlfip'm'aiu therein in urti@ tu impari a. v cipi'ocatiug mohm to aS to cause the -griiuiing' w traverse ihe A'Jrii iii :zu nxiai i i'ei'ipi'ocnting iiiC-x'nwnts irelupin siecve G automziicaiiiy by the i-utu'y ment of the ciuufic-carn" emi of Simms il 11s u cn taining a.

projexiug www: ihm of this Simi inst a isuuuif Whia permitting il" im from im stamt iongiudinai sieeve 5.

thc @Vimi- .313 hy u yiuuigm' fil mounted iu 1 naming iu iie iwgr 20.

iumui in iiuimfm' a. wifi; :imi the i'mviua'mi volition uiu fini:

nai-:1. Shcmiinv mam

i Ofi fixed to the frame et its top the handle and normally entendis f loosely in a socket in the lever, this seing ine position of the parts' when the volles by the com as shown in Fie: l entlne handle is Withdrawn to disengsge t e sollen the pin will be drown ontvgesdly socket, end then by giving elle slight circumferentialftuzn, and releasing i i, the spring will act to (lisw the handle in, wardly and will seat the pin against the outer side of the lever; Wlieieloy the pl gen will be held outwardly with the 4lief disengaged from t'ne'esni. Whentlie open ating means for the reciprocating, freine are thus disconnected, the i'ierne lie seein roca/ted by lionel by Ineens of s handle and laterally therefrom? es shown roei-re lally inFig. 2.

'The adjusting oscillating sise-l alluded to, is mounted inail eccentric 'o .ing in the sleeve 6, the dispose the 'center of sleeve' 7 e e. the center of sleeve S; 'one th.; i so mounted within sleeve 6 that s. eating movements of sleeve 6 will, corresponding movement to sleeve "Ii ons 'the latter will be, pemittsd to oe oseillsted 'eiscumferentially Within sleeve ihs es tions are effected by 'the following described means. The fest'end oi sleeve l is'enlsigfed and is provided with en annule? sho-elder 36 which beers egelns the Peer end of sleeve 6, the enlarged end sleeve 7 being We vided with a circuler seat or secliet 32? wnicli is disposed eccentrically Willi relation to the Center of the -sleeve es shown in Fig. il. ln

members and interoosed entiiii'ieti i. halls., the wheelcerrying 8 mounted centrally within the member.' As a result-oi this consti-notion and arrange ment, the axis of the .wheel cui ingr spindle will be disposed to one side oi? the exis olf the sleeve 7, the eceentic openings in the sleeves 6 and 7 being' opposiiely to each other, thereby causing the exis el the wheel'spindle 8- to be disposed coinciden; with the axis of the chuck ceirying sleeve 5, for the purpose presently to he deseiilsed. At its opposite end'tliev besiing spindle 8 is f mounted in a bearing sleevelll which is tapered exterior-ly and firmly sea-ted in tapered opening in tlieemvmgcl yend o-f-sleeve 7, the benring sleeve 39 being' 4disposed eccen trically kwith relation to the axis of tlie sleeve 7 to eoljrespond to the eccentric relation of the bearing-:it the opposite end of the spindle, to seid sleeve.' The' entii'rrictlon 'ng 38 at the rear end of the wheel spindle is confined in its sent or Sofitel; in the sleeve,` by means of :i screw esp l@ which is screwed. into'tlie end of the enlsig'ed poi tion ofthe sleeve and besisegoinst the este? to moire deeply therein.

tsl i'ansveisely extending yokel, one end el* which is pivoted on a. lioiizontsl stud 4:2l

extend freine is lioini l with s. slot engaging over a stud ,n i resiwsrtllyiom the arm 161", ttes sind heilig three-:led to receive e not lay which the yoke may be i'eni'oveloly in operative position en- Qed with the este? end of the screw cap 'lfiie eleet of the engagement. of the yoke with the screw csp is to forme co11- section lie een the ecipi'ocoting frame 15, end the' sl eve 7 of suoli character that the. o i ling; :movement o fname 15 will 'l wl it and the opposite llame will move the sleeve posii'e eliieetion diie to the engagee end of sleeve 6 with the annular slionldei' 3 le is seen tlieieore'that by the iecipfeesi'zingg movements of frame 15 an( eonseqnently the sleeve 6 clamped therel will be eeciprocated in like man'- ieiwerdly from the erm 16 of w eve Y, will loe likewise reci@- ioeeteo., tliese parts ell moving together es s unit in an axial diiection, with the Wheelspindle espoir/ie oi en independent sotation liin'sleeve 7,. and sleeve 7 being capable oscillating movement ofi en n'xdependent Within sleeve 6.

i l'y season oi 'lie eccentric mounting of the wheel esi' spindle within sleeve 7 as des and by 'season of ,the faei; nozvnelly theeentei oi spindle 8 is coincident with 'die exis of the chuck earz/ing; sleeve `57 when sleeve 7 .is oscillated. Within sleeve ll, the Wheel spindle willv be moved liodily 'radially beyondl its central positios; and tlie grindingwlieel on thespindle` vill loe correspondingly led to the Work so The meehfoioseilloting the' sleeve 7 tol eecl', this radial adjustment oi the grinding wheel eensists of the following. parte. Snrrolinding the enlarged end of sleeve .and iirmly j fix-ed tlieieto, is esegment worm' gesl' 45 engaged at lower ,side ley e, hoi'izontsl trans# vesrsely extending svoinflfe' mounted forerotellen on s soppo'i'ting stud 7. `The Worm is provided with anextension or sleeve 48 (Fig. vfito which y is xedly connected a fknuiled tui'ning. csp

eop, whieli sleeve is with outei end ol the sup-0 is o hori-onso ile the other end of the yoliewheel-carrying spindle 8' inneren tions preferably to 'l/lOO/O orf an inch, adapted to he read in c 1=nnecsion with a lined pointer Til. The gradnatea'l sleeve is clamped to the turningv cap so as to move with it, and is adapted to he released therefrom, to permit the sleeve to he turned to adjust the same to zero, ny means oi a clamping screw 52 threaded centrally into the extension on the worin, a d havine a tapered end which is adapted to engage the inner end of a radially extending locking,l pin mounted 'to slide in the extension of the worm and adapted at its outer end toengage and sind against the inner side oi the graduated sleeve. Normally the screw is adjusted soas to etiect a clamping connection i e i tween the. vworin and the graduated sleeve,

so that when the turning cap is operated to rotate the worm` theI graduated sleeve will move with it. When the sleeve is to he set to Zero 'for another grinding operation, clamping screw 52 loosened, wliicli, releasing the graduated sleeve, permits the latter to he freely turned.r relatively to the worm.

rlie stud il on which the worin lll is mounted, carried by an up and down movanle arm pivotallv sustained on the shaft i8 heiiore alluded to, so that the worin may' he disengaged from the worin wheel by the downward movement ot' 'the arnn and maj,7 be engaged therewith h v swinging the arm up'w'ardly. The arm is held normally in its upper position oy means oi" a spiral spring 55 connected atl its lower end with an angular ting'er fili. projecting reai'wardl)Y from the end oi the shaft, the inn-ingf being connected at its upper end to a washer BT sustained hy the stud ou the frame ie springt, pulling up on the angular arm, forces they saine upwardly agains;I a pin 5S proiecingr outwardlyr from the arm 3i, and hy this means the arm is held yieldinglv in its upper position with the worin engaged with the worin wheel. The washer to which theupper end of the spring' is connected. is arranged ri "tiealij,Y over the axis oi' the shait iti. and liv wir ngz said shaft liv means olf a handle "iiereon, in a direction to carr)y the angular arm 5G so die opposite side of the axis oi tire shai to the position shown liv dottei lines in Fig. (l. the lower the spring;` will he eaused to g and will hold the arm in this po. Ation. i

ariion, nieasing the swinging arm 5l iw disengafl l r arinvironi trie p' thereon. 'the arm ani, he worm i ther 'h v will '#viug downw wlv hv 'the r ight oi' the parts, and the ,nin `will lie disengaged "troni the. worin wheel. This mechanism is rmpioed when desired, after the worin s h in operated hy hand, to graduali freed 'the finding wheel to the work, to qui v return the glnffng' its former inner'gjositien ier another eration, and in eiecting this action, thehandle 59 is swung to the right, which permitting' the worm to descend from engagement with the worm Wheel, as just described, will leave the worm 'Wheel free to he quicl'ily` operated by hand to' restore the wheel to its former initial position, an upwardly eX tending handle 60 being fixed to the upper Side ot the worm wheel tor manual operav tion of the Same. t

ln the operation of the machine, the, casing member ot the hearing is held by the chuck, and the grinding wheel occupies the position shown in Fig. lwith its axis coincident with the axis ot the chuck-carrying sleeve and likewise coincident with the axis of the work held by the chuck thereon, the

scale on the graduated sleeve 50 being set at Zero. `Rotary motion heinscy imparted to the chucleearrving sleeve and to the whcel-car i, 'ng spindle, through the medium of the driving pulley 6l, 'the work carried hy the ffincl; will he. rotated, and by means of the driving' connections loetween the chuclecarrving' sleeve? a ad reciprocating frame l5, the latter will he, moved forwardly and will ad rance the. grinding wheel and cause itto act on the. interior surface ot'. the bore in the work, he wheel, after its advancing movement, being' moved rearwardly and thus reeiprocated hack and forth within the hoi-e of the work. Duri.. such reciprocating movements ot the whceh itis fed radially'fso as to eut' deeper into the work, by moans of the turning cap 'i9 on the end of worm lli, the turningmovement ot' this cap causing the adjusting sleeve 'i' to oscillate circumfereiitially, and by reason of `the eccentric mounting ot the wheel spindle within this sleeve, causing thelatter to move from the center radiali)7 outward, transversely of the axis ot the chuck carrying sleeve.v This action ot the parts is continued until the hor'e the work has been given its desired and iinished surface. 1sl/dien the operation is rompleted. the workl is removed from the chuck, and the lindle 59 on shaft 1S being swung' to the right, worm #i6 will he lowercd'out ot' engagement with worm wheel l5, and the latter ma): he moved b v handle G0 in order to return the grinding wheel quickly inwardlj,7 to its former central position. Clainnin'g screw is then loosened in order to release the graduated sleeve. and the latter is turned o v hand to zere position again.

on arm 18 swunga to the left in order to again engage w ,rm lo with worm wheel l5. The parts are now in condition for operation on another bearing' member, which -is inserted in the chuck, the foregoing operations repeated.

Ars the. Lgrinding wheel acts on the ends of tieren' is 'then tightened up, and handle ith-e here, ior a time but a portion oi' the surlace ci the Whse/i is in grinding engagement ,130

rection of the axis of the here.y and mea-ns Yfor accelerating said 'feeding motion 'when the tool is acting at the end ci the bore.

5%. in a machine' for shapingr the bores or' annular worliforms, the combination of means for rotating the. work about the axis of its bore, a rotary operating wheel, means for imparting to said wheel a feeding niotion in t le direction of the axis oi the bore7 and means for .accelerating?7 said feeding motion when the wheel is acting at 'the end of a bore; whereby the liability of the production of bell mouthed bores is minimized. l

9. in a machine for shaping the hores of annular work-forme, the combination of means for rotating,l ille work about the axis of its bore, a. rotary spindle provided with a grindingvwheel, Said spindle 'mounted reciprocate endwise so as to. canse the wheel to traverse the bore lengthwise thereof', and driving mechanism for 'reciprocating said spindie, said driving mechanism including a cam so shaped as io acceierate the endwiee movements of the spindle when the grinding wheei is operating'at the ends of the boro 10 In a machine for shaping the bores of annular Werl; forins,-the conibimition of means for holding the work with the bore exposed, an operating tool to act on the bore, and means for eecting a relative feeding motion between the work and tool in the direction of the axis of the bore of the work, said means inciuding 'a cam, shaped to accelerate the feeding motion when the grinding Wheel is operating at the end of the bore.

11. In' a machine of the type described, the combination of a frame, a rotary tool spindle adapted to carry an operating toni, a rotary work spindle adapted to vcarry a work holder, one of said spindles being mounted for endvvise reciprocation, a rotary ,driving cam', a vibratory member operated by the cam and operatively connected with the reciprocatin'g spindie for reciprocating the saine, and means for disconnecting the cam from driving engagement with the vib; tory member.

152.1In a machine of the type described, the combination of a frame, aspindle adapted to carry an operating tool, a rotary wom Work' holden; one ci said si'iindles being mounted for eadwise reciprocaiion, a rotary driving; cam, avibratory member, a roller on said vibratory member engaged by the driv ing cani? said roller being movable at will to disengage the cam, and operative connections between the vihratory member and the reciprocating spindle for reciprocating the same.

13. In a mechineot the type dcecrihed, the combination Vof a iframe, a rotary tool spindie adapted to carry an operating tool and mounted for endwise reciprocation, 4a rotary rotary tool;

spinclie adapted to carryT a Licentie -vork spindie adapted to carry. a Work" holder, a worm on the work spindle, a Worm wheel engaged and rotated by the worm, op

endwise from the supporting sleeve, releasallie meansl'or' holding the adjusting sleeve in operative relation within the supporting seeve, and a rotary tool spindle mounted. within the adjusringsleeve and adapted to rai-rvy a grinding tool.V

l5. la a machine of the ltype described,

he combination of a frame, a rotaryWorkA therein and adapted to. carry sleeve mounted a work holder, a supporting sieeve mounted for reciprocation within. the Work sleeve, av frameto ehe supporting sleeve; means for reciprocating said iframe to impart ,a gte? ciprmatiug;r motion to the supporting s'feove, an adjusting sleeve mounted wi porting sleeve and provided Wien an annular shoulder engaged by the supporting sieeve to cause the adjusting sleeve to he moved with the supporting; sieeve in one direction, a yoke carried by frame and. en-

gaging the end oi the adyusting sleeve to canse the latter to be moved by the supporting" sleeve in the opposite di1ection,'and a rotary tool spindle mountedvivithin the arljusting sleeve and movahie'therewith in the reciprocations of the same.

ii. ln a machine of the type'described, the combination' of a iiframe, a rotary Work sicere mounted therein and adapted to carry. a work holder, a supporting sieeve mounted forreciprocation within the'work sleeve, a frame fixed to ihe supporting eieeve, means for reciprocating;said frame to impart a reciprocating motionV Sleereaan adjusting sleere mounted within the supporting sleeve and noi-ided'with an annular shoulder engaged by the supporting sleeve to canse the adjustinfl' Sleeve to be moved with the supporting ve in onev irectioin a rohe carried by the frame and. er1- gagingxvthe end of the adjusting l*ve to cause the latter to be mg sleeve 'in the opposite direction, said yoke being movable to disengage the adjust- 'me' sleeve to permit the latter to be removed from within the supporting sleeve, and a rotary tool spindle mounted ,within the a.d justiner rcriprocations ol'V the saine.

17. ln a machine of the type describem'. the combination of a main frame, a rotary sleeve and movable therewith in the to the supporting- .1205, moved by the support- Y Work sleeve mounted therein anc?. adapted to curry a Work hoicler, a supporting sieeve mounted for reciproeation Within the work sleeve, a toni spindle mounted Within the supporting sleeve and reoiuroeuting therewith, a traine applied 'te theeupporting sleeve, a rotary driving member, and o erative connect-ions'between the rotary t Ning member and the 'frame for reeiprocutiiw' tile latter to impart a corresponding reeiprooa tion to 'the supporting sleeve.

18. In a machine of the type fieseriherl, the combination of a fram-e, a rotary werk sleeve mounted therein and adapted to Carry a Work holding device, a supporting sleeve mounted to reciprocate endwise Within the Work sleeve, an oscillating adjusting slee-'ve mounted within an eccentric opening in the supporting sleeve and v niovabie enclwise therewith, and a rotary tool carrying spindle mounted eceentrically within the adjusting sleeve yand movable endwise therewith, the eccentric inountings of the .seid adjusting sleeve and tool spindle being eppositely disposed. v v

lil-In a machine of the type described, the combination of a rotary Work spindle adaptedto carry u Work hohier, a. rotary tool spindle adapted to carry an .operating tool7 one of said spindles being adjustable radially with respect to the other to cause the tool to enter the material oit the work,

and an adjusting member operatively env gagerl 'with the adjustable spiudie for arijusting the same, said member being movable to (,liseugagethe. spindle to permit the latter to he adjusted hv hand.

20.111 a machine or the type useribed, the combination of a. frame, rotary Work sleeve mounted thereinantl adapted te carry a work holder, an adjusting sleeve mounted ecrentrioally mithin the- Work sleeve. and oscillatahle oir-cumferentieiiy therein to ef feet its rzuliai adjustment, a rotary tuoi spin- (lle carried by the adjust-ing sleeve anti fuif justahle with it to cause the tool to enter the material of the work, a gear on the atijusi3- ing sleeve, and an adjusting member enthe gear for oseiilating it, sai'ii fuif gustmg niemeer heine' movable to dlsengage the geen to permit. the .sleeve to be adjusted. by hand,

En a niaehine the type'described, the combination of a. frame, a rotary Work si i'eniounted therein and adapted to carry Jerk holgier, an adjusting sleeve mounted intriealiy within the Work sleeve and r llatahle rireunifereutiaily therein to e- 'ect its redini adjustment, a rotary tool a AWork holder, un adjusting sieevexnounted eccentric-ally 'Within the Work-.sleeve and oseiilataoe eireuniferentialiy therein, a rotary 'toel spindle carried by the adjusting sleeve adjustable with it to cause the tool to enter the material of the Work, a gear on theadjusting sleeve, a swinging urru, an ajusting member Aniounteol in the arm aud'engaging the'gear for oseiilating the latter, said member adapted to be disen raged from the gear by the swinging movement of the ann, and u Spring acting on the arm and tending to hoiei the member yieling y in. engagement Wil the gear, the relation of the parts heingsuch that when the arm. isswung to disengage the. member from' the gear the spring will act to hold the. same yieiriingly disengage.

in testimony whereof, have affixed my signature in presence of two Witnesses.

FRED E. BRIGHT.

itnessesz CHARLES BUTLER, Bsu'rini KING. 

